Cyclone separators are well-known devices for separating solids from gases and gases from liquids. Some typical cyclone separator designs are illustrated in Perry's Chemical Engineers' Handbook, published by McGraw-Hill Book Company, New York City.
The use of vanes within cyclones is well-known. They are used to guide the flow of gases and minimize entrainment of liquids or solids. U.S. Pat No. 3,969,096 (Richard) discloses a cyclone separator having multiple vaned gas inlets. The gas inlet consists of elongated inlet openings (like those of a louver) positioned to deflect incoming gas in a circular path from the gas outlet tube.
U.S. Pat. No. 3,707,830 (Gustavsson) discloses a cyclone separator having a cylindrical shell with a conical converging inlet portion. A ring of guide vanes is positioned within the outlet to impart a rotational flow to the entering gas. The ring is axially moveable.
U.S. Pat. No. 5,683,493 (Stober) discloses close packed cyclones similar to those depicted in one embodiment of the instant invention. In the preferred embodiment, however, vapor and entrained liquid are directed upward in a rotational fashion by tabs in the base of the cyclone. The instant invention discloses close-packed cyclones in which one embodiment does not possess a spinning zone at its base.
FIG. 1 shows a cyclonic device for vapor/liquid contacting in which liquid is introduced near the floor of the cyclone. The barrel is drawn with dashed lines, to distinguish it from the other parts of the device. Preferably, liquid is introduced through a downcomer tube located axially in the cyclone barrel, as shown in FIG. 1. Alternately, it may be introduced through a plenum, which is fed by a downcomer from the tray above (this embodiment is not depicted).
As vapor rises through the base of the cyclone, it passes through orifices which impart a spin to the vapor. As patents such as U.S. Pat. No. 3,969,096 demonstrate, the concept of devices, such as vanes, to impart spin located at the inlet of the cyclone is known. Preferably, these vanes are formed integrally with holes in the base of the cyclone. The gas then imparts a rotational action to the liquid. The liquid is preferentially thrown to the outside of the cyclone. Openings in the barrel of the cyclone allow the liquid to exit from the cyclone. Flaps or baffles in or near these openings may be used to help direct liquid out through the openings. An annular hat above the barrel may also be used to capture liquid emerging from the top of the barrel and to direct this liquid downward. If the conventional device depicted in FIG. 1 is used, the liquid can dampen the spin action of the vapor. This reduces the liquid collection efficiency in the cyclone.
U.S. Pat. No. 3,498,028 (Trouw) illustrates a vessel for contacting liquid and vapor when a large supply of liquid must be accommodated. Liquid is added at the base of the vessel through a horizontal tube extending inward toward the center. Vapor rises into the vessel vertically. Vapor and liquid mix at the base of the vessel, and vapor rises with entrained liquid.
G.B. 1,070,777, assigned to Shell International Research, illustrates a tray for mounting in a column for liquid/gas contacting which possesses at least one tubular liquid/gas contacting device, which is located at the base of the column. In U.S. Pat. No. 5,683,629, the liquid delivery device first disclosed in G.B. 1,070,777 further comprises a plurality of parallel channels having upwardly directed openings. This increases the entrainment of liquid in the gas, thereby improving heat transfer.
In conventional cyclones, spin is imparted to the vapor and entrained liquid after it enters the cyclone via a downcomer or plenum. The vapor and entrained liquid then moves upward,entering a zone where liquid is removed via slots or other perforations in the barrel or by an annular hat in the top of the barrel.